Dental caries (e.g., tooth decay or cavities) is a disease that affects an individual tooth, which is repaired by restorative treatment when sufficient tooth structure remains to allow for such repair. When caries is sufficiently advanced, an affected tooth is extracted and, if desired, the dentition is repaired by prosthetic treatment that replaces the lost tooth with a prosthetic tooth. Severity is a term that can be used to describe the size of a carious lesion and extent can be used to describe the number of carious lesions in a dentition. In some examples, as shown in FIG. 1, severity can be defined as a linear extension by the depth of penetration from the outer tooth surface to the pulp. Dentist's use the carious lesion's severity to determine the type of treatment from the categories of preventative, restorative, or endodontic interventions. In some additional examples, severity can be defined by the three-dimensional configuration or volume of tooth structure destroyed, which dentist's use to determine if the tooth is restorable and the type of restoration indicated.
Dental caries is site-specific, which means that a dentition may have multiple independent sites of disease and multiple independent treatment interventions. Dentists often describe the status of the patient's dentition in very simple terms and from a perspective of treatment need using the number of teeth with caries and the number of teeth that need to be replaced. More sophisticated methods to describe a dentition have been developed for use in dental research but are not typically used for patient communication due to a lack of utility for this purpose. Existing dental indices include Decayed/Missing/Filled Teeth (DMFT), Decayed/Missing/Filled Surface (DMFS), Significant Caries Index (SiC), and Extrapolated Carious Surface Increment Index (ECSI).
DMFT describes the prevalence of teeth affected by dental caries in an individual. It is calculated by adding the number of decayed (D), missing (M), and filled (F) teeth (T). The score range is 0 to 28. The score and its component measures are sometimes used by public health organizations to determine dental status and treatment needs for a population. A DMFT score only increases and does not decrease with treatment. The only direction it can move is higher as the index increases with each tooth newly decayed or missing or filled.
DMFS differs from DMFT by substituting surfaces (S) for teeth (T), which results in a range of 0 to 128 for an adult. The SiC (Significant Caries Index) index is the mean DMFT of the one third of the study group with the highest caries score. The index can be used as a complement to the mean DMFT value.
ECSI (Extrapolated Carious Surface Increment Index) is a caries progression index, which takes into account the enlargement of existing lesions as well as the initiation of new ones.